This application seeks support for a multi-disciplinary training program for outstanding pediatric clinical fellows at the University of Pittsburgh School of Medicine/Children's Hospital of Pittsburgh in the translational aspects of molecular and cellular biology. Our specific aim is to prepare physician-scientists for independent academic careers in pediatric subspecialties, emphasizing the clinical application of basic science advances. Our program will involve two to three years of laboratory-based research beyond the first year of clinical fellowship training. While the clinical year will center on activities at Children's Hospital of Pittsburgh, the subsequent research years will be supervised by a committee of faculty selected from the University of Pittsburgh School of Medicine academic community. These faculty are all established senior investigators, selected because of the immediate translational relevance and high quality of their research, their long-term productivity and success at securing extramural funding, their outstanding records of postdoctoral fellowship training, their common interests, and penchant for working beyond the narrow boundaries of their own research areas/specialties. In addition to providing some of the actual training venues for our fellows, these individuals will serve as members of individually tailored Project Committees that will oversee, evaluate, and guide the scientific and intellectual progress of each fellow. Trainees will work side-by-side in a laboratory with other M.D., Ph.D. and M.D./Ph.D. predoctoral and postdoctoral trainees. Periodic evaluation, coupled with formal course work, will offer a rigorous intellectual foundation for each fellow's scientific endeavors. Together with the University of Pittsburgh School of Medicine, Children's Hospital of Pittsburgh has just committed 250 million dollars to pediatric research over the next 10 years. This commitment will be used to build a second pediatric research building of 100,000 new square feet to go with the current pediatric research building of 110,000 square feet and to recruit 30 new principle investigators/research programs. Based on the excellent trainees already accepted for FY02 and increasing number of candidates under consideration for FY03, support for four postdoctoral fellows per year is requested. We anticipate that this will be composed of two fellows in their first year and two fellows in their second year of laboratory training, but the program will be designed to facilitate the transition of each of these trainees onto their own mentored scholar awards (K series) or into a new Children's Hospital of Pittsburgh-endowed Advanced Fellowship Training Program so that there is at least four-five years of research training planned for each fellow. Using these strategies, the program will serve as an incubator that will supply our institution with a significant source of high-quality pediatric scientists to meet our own future needs as well as those of other national and international institutions.